A coach/principal locally that helped us call some elementary games years ago had a very good quote: "It's like I'm deer hunting. I'm aiming the gun, aiming the gun, aiming the gun, but by the time I know what I was shooting at, the deer is gone."
My translation: Don't be afraid to blow the whistle a little late. Better to be late and right than to be on time and wrong. You're thinking: "He did it....No, wait...I think..." and about that time a coach or a fan yells out the call. Even if the call you hear is correct, it tends to make you freeze. All this is just food for thought in case you run out of things to worry about.
